readme: kickstart a proper readme

Signed-off-by: Ciro S. Costa <utxobr@protonmail.com>

README.md

@@ -1,8 +1,118 @@
 # go-monero
 
-total wip, a few useful tools for debugging monero's daemon && p2p.
+A Go library (and CLI) for interacting with Monero daemons via RPC or the P2P
+network free of CGO, either on clearnet or not.
 
-## levin
+- want/need help? reach out to `utxobr` on https://matrix.to/#/#monero-community:matrix.org
+
+## Quick start
+
+### library
+
+`go-monero` exposes two high-level packages: `levin` and `daemonrpc`.
+
+The first (`levin`) is used for interacting with the p2p network via plain TCP
+(optionally, Tor and I2P can also be used via socks5 proxy - see options). For
+instance, to reach out to a node (of a particular address `addr`) and grab its
+list of connected peers (information that comes out of the initial handshake):
+
+```golang
+import (
+        "fmt"
+        "context"
+
+        "github.com/cirocosta/go-monero/pkg/levin
+)
+
+func ListNodePeers(ctx context.Context, addr string) error {
+	client, err := levin.NewClient(ctx, addr)
+	if err != nil {
+		return fmt.Errorf("new client '%s': %w", addr, err)
+	}
+
+	defer client.Close()
+
+	pl, err := client.Handshake(ctx)
+	if err != nil {
+		return fmt.Errorf("handshake: %w", err)
+	}
+
+	for addr := range pl.Peers {
+		fmt.Println(addr)
+	}
+
+        return nil
+}
+```
+
+The second (`daemonrpc`), is used to communicate with `monerod` via its HTTP
+endpoints. Note that not all endpoints/fields are exposed on a given port - if
+it's being served in a restricted manner, you'll have access to less endpoints
+than you see in the documentation
+(https://www.getmonero.org/resources/developer-guides/daemon-rpc.html)
+
+For instance:
+
+```go
+import (
+        "fmt"
+        "context"
+
+        "github.com/cirocosta/go-monero/pkg/daemonrpc"
+)
+
+func ShowBlockHeight (ctx context.Context, addr string) error {
+	client, err := daemonrpc.NewClient(addr)
+	if err != nil {
+		return fmt.Errorf("new client for '%s': %w", addr, err)
+	}
+
+	resp, err := client.GetBlockCount()
+	if err != nil {
+		return fmt.Errorf("get block count: %w", err)
+	}
+
+        fmt.Println(resp.Count)
+	return nil
+}
+```
+
+
+### cli
+
+```console
+$ GO111MODULE=on go get github.com/cirocosta/go-monero/cmd/monero
+
+$ monero --help
+Usage:
+  monero [OPTIONS] <command>
+
+Application Options:
+  -v, --verbose  dump http requests and responses to stderr [$MONEROD_VERBOSE]
+  -a, --address= RPC server address [$MONEROD_ADDRESS]
+
+Help Options:
+  -h, --help     Show this help message
+
+Available commands:
+  crawl                 Crawl over the network to find all peers
+
+  p2p-peer-list         Find out the list of local peers known by a node
+
+  get-block-count       Get the block count
+  get-block-template    Get a block template on which mining a new block
+  get-coinbase-tx-sum   Get the coinbase amount and the fees amount for n last blocks starting at particular height
+  get-connections       Retrieve information about incoming and outgoing connections to your node (restricted)
+  get-fee-estimate      Gives an estimation on fees per byte
+  get-info              Retrieve general information about the state of your node and the network. (restricted)
+  get-transaction-pool  Get all transactions in the pool
+  on-get-block-hash     Look up a block's hash by its height
+  sync-info             Get synchronisation information (restricted)
+```
+
+## TODO
+
+### levin
 
 - [x] header
 - [x] payload
@@ -10,9 +120,9 @@ total wip, a few useful tools for debugging monero's daemon && p2p.
   - [x] deserialization
 - [ ] properly typed structures
 
-## daemon
+### daemon
 
-### json rpc
+#### non-jsonrpc
 
 - [ ] `flush_txpool`
 - [ ] `get_alternate_chains`
@@ -39,8 +149,7 @@ total wip, a few useful tools for debugging monero's daemon && p2p.
 - [x] `on_get_block_hash`
 - [x] `sync_info`
 
-
-### json rpc
+#### json rpc
 
 - [ ] `/get_alt_blocks_hashes`
 - [ ] `/get_blocks.bin`